Classification of malocclusions, Part 3

In a proper bite, the upper teeth, viewed from the front, close outside of the lower teeth. In the back of the mouth, the upper teeth have to cover the lower teeth. When this does not happen, that is to say, when the lower teeth are outside of the upper teeth, this is called a crossbite.

This image shows an ideal bite; the upper teeth cover the lower teeth in the back of the mouth.

A crossbite may result from a narrow palate, a very wide lower jaw or a combination of both in a single patient.

A crossbite is one of the most common malocclusions and requires early treatment. Treatment tends to consist of palatal expansion, although other procedures may be required, depending on the cause.

If the patient is being treated at an early age, treatment tends to consist of expansion with expansion appliances. If the patient is being treated in adulthood, treatment tends to consist of compensation (for a crossbite) or orthognathic surgery.